George K, Hoang HTM, Tibbs T, Nagaraja RY, Li G, Troyano-Rodriguez E, Ahmad M. Robust GRK2/3/6-dependent desensitization of oxytocin receptor in neurons.
iScience 2024;
27:110047. [PMID:
38883814 PMCID:
PMC11179071 DOI:
10.1016/j.isci.2024.110047]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 02/22/2024] [Accepted: 05/17/2024] [Indexed: 06/18/2024] Open
Abstract
Oxytocin plays critical roles in the brain as a neuromodulator, regulating social and other affective behavior. However, the regulatory mechanisms controlling oxytocin receptor (OXTR) signaling in neurons remain unexplored. In this study, we have identified robust and rapid-onset desensitization of OXTR response in multiple regions of the mouse brain. Both cell autonomous spiking response and presynaptic activation undergo similar agonist-induced desensitization. G-protein-coupled receptor kinases (GRK) GRK2, GRK3, and GRK6 are recruited to the activated OXTR in neurons, followed by recruitment of β-arrestin-1 and -2. Neuronal OXTR desensitization was impaired by suppression of GRK2/3/6 kinase activity but remained unaltered with double knockout of β-arrestin-1 and -2. Additionally, we observed robust agonist-induced internalization of neuronal OXTR and its Rab5-dependent recruitment to early endosomes, which was impaired by GRK2/3/6 inhibition. This work defines distinctive aspects of the mechanisms governing OXTR desensitization and internalization in neurons compared to prior studies in heterologous cells.
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